The subject matter disclosed herein relates to systems and methods for adhering coatings to substrate structures and more particularly to a method for reducing inelastic deformation of coatings applied to rotating components.
In rotating machines, such as turbine engines, components often include a coating to achieve a desirable performance, durability and/or life attribute of the components. For example, coatings may be configured to resist oxidation, erosion, heat transfer, contamination, and/or other processes. Such components typically comprise a substrate structure configured to satisfy a first set of design objectives and a coating that is bonded to an outer surface of the substrate structure, with the coating being configured to satisfy a second set of design objectives. The design objectives for a substrate structure may address mass limitations, structural requirements, and aerodynamic shape considerations while the design objectives for a coating may address different considerations such as adhesion to, and protection of, the substrate structure. Thus, the substrate structure typically, though not exclusively, comprises a different material than that of the coating. As a result, a rate of thermal expansion for the substrate structure may differ from a rate of thermal expansion for the coating, causing stresses at the bonds between the substrate structure and the coating.
In rotating machines, such as turbine engines, rotating machinery may be subjected to large radial accelerations, causing sustained high forces within their subject components. In addition, some components, such as turbine blades, may also be subjected to high temperatures. As a result, bonds between the substrate structure and the coating may be challenged. In some cases, the stresses applied to coated components can cause viscous or inelastic deformations in the coatings relative to the substrate structures (i.e., creep), with such deformations typically occurring in the direction of the loads. In rotating components, the direction of the loads is typically the radial direction.
Therefore, those skilled in the art seek new systems and methods for reducing inelastic deformation of coatings on rotating components.